Renewable energy has become a major focus for energy and environment sustainability. Wind is an example of an appropriate energy source for utility-level power generation. The power generation for wind turbines may be substantially affected by the aerodynamic characteristics of wind-turbine interaction. For example, the amount of power extracted from the wind may in part depend on the aerodynamic angle of attack between the rotor blades and the incoming air flow. If, for a given wind speed, a certain maximum angle of attack is exceeded, the air flow can separate at the surface of the rotor blades and vortices may form. This effect is known as flow separation and limits the aerodynamic efficiency of the blades to extract power from the wind. This may substantially increase acoustic noise generated by the wind turbine.
Certain vibration-sensing devices for sensing such a condition have generally been installed into the blades and, as a result, their reliability tends to suffer due to the forces experienced by a rotating object. Other listening devices, which may be located outside the blade, may be subject to acoustic interference and/or may lack the ability to quickly and precisely detect where and when a flow separation condition may be initiated. For example, a flow separation condition may initially develop just in a portion of a blade path swept by a given blade. At least in view of the foregoing considerations, it would be desirable to provide a reliable and cost-effective apparatus for improved detection of such aerodynamic conditions.